Schedule of Segment Reporting Information, by Segment [Table]
Consolidation Items [Axis]
Consolidation Items [Axis]
Consolidation Items [Domain]
Consolidation Items [Domain]
Segment Balances Before Intersegment Eliminations and Consolidation Reconciling Items [Member]
Operating Segments [Member]
Intersegment Eliminations [Member]
Intersegment Eliminations [Member]
Segments [Axis]
Segments [Axis]
Segments [Domain]
Segments [Domain]
United States [Member]
UNITED STATES
Canada [Member]
CANADA
United States And Canada Segments [Member]
United States And Canada Segments [Member]
United States And Canada Segments [Member]
Other Businesses [Member]
Other Businesses [Member]
Other businesses include the results of the following non-material operating segments: MonotaRO Co., Ltd. (Japan), Grainger, S.A. de C.V. (Mexico), Asia Pacific Brands India Private Limited (India), Grainger Carbie Inc. (Puerto Rico), Grainger China LLC (China) and Grainger Panama S.A. (Panama).
Segment Reporting Information [Line Items]
Segment Reporting Information [Line Items]
TOTAL ASSETS
Assets
Summarized Information
Segment Reporting [Abstract]
Net sales to external customers
Revenue from Contract with Customer, Excluding Assessed Tax
Total consolidated operating earnings
Operating Income (Loss)
Debt Disclosure [Abstract]
Schedule of Long-term Debt Instruments [Table]
Schedule of Long-term Debt Instruments [Table]
Debt Instrument [Axis]
Debt Instrument [Axis]
Debt Instrument, Name [Domain]
Debt Instrument, Name [Domain]
Senior Notes, 1.85% due 2025 [Member]
Unsecured Senior Notes, 1.85% [Member]
Unsecured Senior Notes, 1.85% [Member]
5-Year Unsecured Revolving Line Of Credit [Member]
5-Year Unsecured Revolving Line Of Credit [Member]
5-Year Unsecured Revolving Line Of Credit [Member]
Credit Facility [Axis]
Credit Facility [Axis]
Credit Facility [Domain]
Credit Facility [Domain]
Revolving Credit Facility [Member]
Revolving Credit Facility [Member]
Variable Rate [Axis]
Variable Rate [Axis]
Variable Rate [Domain]
Variable Rate [Domain]
Base Rate [Member]
Base Rate [Member]
Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Fed Funds Effective Rate Overnight Index Swap Rate [Member]
Eurodollar [Member]
Eurodollar [Member]
Short-term Debt, Type [Axis]
Short-term Debt, Type [Axis]
Short-term Debt, Type [Domain]
Short-term Debt, Type [Domain]
Line of Credit [Member]
Line of Credit [Member]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Axis]
Long-term Debt, Type [Domain]
Long-term Debt, Type [Domain]
Domestic Line of Credit [Member]
Domestic Line of Credit [Member]
Senior Notes [Member]
Senior Notes [Member]
Debt Instrument [Line Items]
Debt Instrument [Line Items]
Debt principal amount
Debt Instrument, Face Amount
Interest rate
Debt Instrument, Interest Rate, Stated Percentage
Line Of Credit Facility, Option To Increase Maximum Borrowing Capacity
Line Of Credit Facility, Option To Increase Maximum Borrowing Capacity
Line Of Credit Facility, Option To Increase Maximum Borrowing Capacity
Basis points
Debt Instrument, Basis Spread on Variable Rate
Redemption price, percentage upon change of control
Debt Instrument, Redemption Price, Percentage Upon Change Of Control
Debt Instrument, Redemption Price, Percentage Upon Change Of Control
Redemption price
Debt Instrument, Redemption Price, Percentage
Debt issuance costs and discounts, net of amortization
Debt Instrument, Unamortized Discount (Premium) and Debt Issuance Costs, Net
Maximum availability of revolving credit facility
Line of Credit Facility, Maximum Borrowing Capacity
Borrowings under lines of credit
Proceeds from Lines of Credit
Effective interest rate
Debt Instrument, Interest Rate, Effective Percentage
Outstanding lines of credit
Line of Credit, Current
Derivative Instruments and Hedging Activities Disclosure [Abstract]
Derivative [Table]
Derivative [Table]
Hedging Designation [Axis]
Hedging Designation [Axis]
Hedging Designation [Domain]
Hedging Designation [Domain]
Designated as Hedging Instrument [Member]
Designated as Hedging Instrument [Member]
Hedging Relationship [Axis]
Hedging Relationship [Axis]
Hedging Relationship [Domain]
Hedging Relationship [Domain]
Fair Value Hedging [Member]
Fair Value Hedging [Member]
Cash Flow Hedging [Member]
Cash Flow Hedging [Member]
Derivative Instrument [Axis]
Derivative Instrument [Axis]
Derivative Contract [Domain]
Derivative Contract [Domain]
Interest Rate Swap [Member]
Interest Rate Swap [Member]
Derivative [Line Items]
Derivative [Line Items]
Derivative, notional amount
Derivative, Notional Amount
Derivative instruments and hedges, liabilities
Derivative Instruments and Hedges, Liabilities
Statement of Financial Position [Abstract]
ASSETS
Assets [Abstract]
CURRENT ASSETS
Assets, Current [Abstract]
Cash and cash equivalents
Cash and Cash Equivalents, at Carrying Value
Accounts receivable (less allowances for doubtful accounts of $24 and $21, respectively)
Accounts Receivable, after Allowance for Credit Loss, Current
Inventories - net
Inventory, Net
Prepaid expenses and other current assets
Prepaid Expense and Other Assets, Current
Prepaid income taxes
Prepaid Taxes
Total current assets
Assets, Current
PROPERTY, BUILDINGS AND EQUIPMENT - NET
Property, Plant and Equipment, Net
DEFERRED INCOME TAXES
Deferred Income Tax Assets, Net
GOODWILL
Goodwill
INTANGIBLES - NET
Intangible Assets, Net (Excluding Goodwill)
OTHER ASSETS
Other Assets, Noncurrent
LIABILITIES AND SHAREHOLDERS' EQUITY
Liabilities and Equity [Abstract]
CURRENT LIABILITIES
Liabilities, Current [Abstract]
Short-term debt
Short-term Debt
Current maturities of long-term debt
Long-term Debt, Current Maturities
Trade accounts payable
Accounts Payable, Trade
Accrued compensation and benefits
Employee-related Liabilities, Current
Accrued contributions to employees’ profit sharing plans
Liability, Other Postretirement Defined Benefit Plan
Accrued expenses
Accrued Liabilities
Income taxes payable
Accrued Income Taxes, Current
Total current liabilities
Liabilities, Current
LONG-TERM DEBT (less current maturities)
Long-term Debt, Excluding Current Maturities
DEFERRED INCOME TAXES AND TAX UNCERTAINTIES
Deferred Income Taxes and Other Tax Liabilities, Noncurrent
OTHER NON-CURRENT LIABILITIES
Liability, Other Postretirement Defined Benefit Plan, Noncurrent
SHAREHOLDERS' EQUITY
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest [Abstract]
Cumulative Preferred Stock – $5 par value – 12,000,000 shares authorized; none issued nor outstanding
Preferred Stock, Value, Issued
Common Stock – $0.50 par value – 300,000,000 shares authorized; 109,659,219 shares issued
Common Stock, Value, Issued
Additional contributed capital
Additional Paid in Capital, Common Stock
Retained earnings
Retained Earnings (Accumulated Deficit)
Accumulated other comprehensive losses
Accumulated Other Comprehensive Income (Loss), Net of Tax
Treasury stock, at cost – 56,191,283 and 55,971,691 shares, respectively
Treasury Stock, Value
Total W.W. Grainger, Inc. shareholders’ equity
Stockholders' Equity Attributable to Parent
Noncontrolling interest
Stockholders' Equity Attributable to Noncontrolling Interest
Total shareholders' equity
Stockholders' Equity, Including Portion Attributable to Noncontrolling Interest
TOTAL LIABILITIES AND SHAREHOLDERS' EQUITY
Liabilities and Equity
Restructuring and Related Activities [Abstract]
RESTRUCTURING RESERVES
Restructuring and Related Activities Disclosure [Text Block]
Accounting Policies [Abstract]
NEW ACCOUNTING STANDARDS
New Accounting Pronouncements and Changes in Accounting Principles [Text Block]
Income Tax Disclosure [Abstract]
INCOME TAXES
Income Tax Disclosure [Text Block]
Organization, Consolidation and Presentation of Financial Statements [Abstract]
BACKGROUND AND BASIS OF PRESENTATION
Organization, Consolidation and Presentation of Financial Statements Disclosure [Text Block]
ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES [Abstract]
ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES [Abstract]
Statement of Stockholders' Equity [Abstract]
Statement [Table]
Statement [Table]
Equity Components [Axis]
Equity Components [Axis]
Equity Component [Domain]
Equity Component [Domain]
Common Stock [Member]
Common Stock [Member]
Additional Contributed Capital [Member]
Additional Paid-in Capital [Member]
Retained Earnings [Member]
Retained Earnings [Member]
Accumulated Other Comprehensive Earnings (Losses)
AOCI Attributable to Parent [Member]
Treasury Stock [Member]
Treasury Stock [Member]
Noncontrolling Interest [Member]
Noncontrolling Interest [Member]
Statement [Line Items]
Statement [Line Items]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Increase (Decrease) in Stockholders' Equity [Roll Forward]
Beginning balance
Stock based compensation
APIC, Share-based Payment Arrangement, ESPP, Increase for Cost Recognition
Purchases of treasury stock
Stock Repurchased During Period, Value
Net earnings
Net Income (Loss), Including Portion Attributable to Noncontrolling Interest
Other comprehensive (losses) earnings
Other Comprehensive Income (Loss), Net of Tax
Capital contribution
Noncontrolling Interest, Increase from Subsidiary Equity Issuance
Cash dividends paid
Dividends, Common Stock, Cash
Ending balance
Other Contract [Member]
Other Contract [Member]
Cross Currency Interest Rate Contract [Member]
Cross Currency Interest Rate Contract [Member]
Interest expense, net
Interest Income (Expense), Net
Other, net
Other Nonoperating Income (Expense)
Fair Value and Carrying Amounts
Derivative Asset, Fair Value, Gross Asset
Revenue from Contract with Customer [Abstract]
Disaggregation of Revenue [Table]
Disaggregation of Revenue [Table]
Product and Service [Axis]
Product and Service [Axis]
Product and Service [Domain]
Product and Service [Domain]
Service Revenue [Member]
Service Revenue [Member]
Service Revenue [Member]
Disaggregation of Revenue [Line Items]
Disaggregation of Revenue [Line Items]
Percent of Total Company Revenue
Percentage Of Company-Wide Revenue
Percentage Of Company-Wide Revenue
Accrued sales returns
Contract with Customer, Refund Liability
Accrued sales incentives
Contract With Customer, Sales Incentive Liability
Contract With Customer, Sales Incentive Liability
Goodwill and Intangible Assets Disclosure [Abstract]
Schedule of Goodwill [Table]
Schedule of Goodwill [Table]
Geographical [Axis]
Geographical [Axis]
Geographical [Domain]
Geographical [Domain]
Goodwill [Line Items]
Goodwill [Line Items]
Goodwill [Roll Forward]
Goodwill [Roll Forward]
Goodwill, beginning balance
Impairment
Goodwill, Impairment Loss
Translation
Goodwill, Foreign Currency Translation Gain (Loss)
Goodwill, ending balance
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Goodwill, Impaired, Accumulated Impairment Loss [Abstract]
Cumulative goodwill impairment charges, beginning balance
Goodwill, Impaired, Accumulated Impairment Loss
Impairment
Cumulative goodwill impairment charges, ending balance
Accounts Receivable and Allowance for Credit Losses, Policy
Financing Receivable, Allowance for Credit Losses, Policy or Methodology Change [Policy Text Block]
Senior Notes, 4.60% due 2045 [Member]
Unsecured Senior Notes, 4.60% [Member]
Unsecured Senior Notes, 4.60% [Member]
Senior Notes, 3.75% due 2046 [Member]
Unsecured Senior Notes, 3.75% [Member]
Unsecured Senior Notes, 3.75% [Member]
Senior Notes, 4.20% due 2047 [Member]
Unsecured Senior Notes, 4.20% [Member]
Unsecured Senior Notes, 4.20% [Member]
Senior notes [Member]
British pound denominated term loan and revolving credit facility [Member]
British Pound Denominated Term Loan [Member]
British Pound Denominated Term Loan [Member]
Euro denominated term loan and revolving credit facility [Member]
Euro Denominated Bank Term Loan [Member]
Unsecured five-year euro denominated bank term loan in connection with the acquisition of the Fabory Group [Member]
Canadian dollar revolving credit facility [Member]
Canadian Dollar Revolving Credit Facility [Member]
Canadian Dollar Revolving Credit Facility [Member]
Long-term debt
Long-term Debt
Long-term debt, fair value
Long-term Debt, Fair Value
Other
Other Long-term Debt
Other, fair value
Other Long-Term Debt, Fair Value Disclosure
Other Long-Term Debt, Fair Value Disclosure
Long-term debt, gross
Long-term Debt, Gross
Long-term debt, gross, fair value
Long-Term Debt, Gross, Fair Value Disclosure
Long-Term Debt, Gross, Fair Value Disclosure
Less current maturities
Less current maturities, fair value
Long-Term Debt, Current Maturities, Fair Value Disclosure
Long-Term Debt, Current Maturities, Fair Value Disclosure
Debt issuance costs and discounts, fair value
Debt Instrument, Unamortized, Discount (Premium) And Debt Issuance Costs, Net, Fair Value
Debt Instrument, Unamortized, Discount (Premium) And Debt Issuance Costs, Net, Fair Value
Long-term debt (less current maturities)
Long-term debt, excluding current maturities, , fair value
Long-Term Debt, Excluding Current Maturities, Fair Value Disclosure
Long-Term Debt, Excluding Current Maturities, Fair Value Disclosure
Commitments and Contingencies Disclosure [Abstract]
CONTINGENCIES AND LEGAL MATTERS
Legal Matters and Contingencies [Text Block]
Statement of Comprehensive Income [Abstract]
Other comprehensive earnings (losses):
Other Comprehensive Income (Loss), Net of Tax [Abstract]
Foreign currency translation adjustments, net of reclassification
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Gain (Loss) Arising During Period, Net of Tax
Postretirement benefit plan reclassification, net of tax benefit of $1 million and $1 million, respectively
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, after Tax
Other
Other Comprehensive Income (Loss), Cash Flow Hedge, Gain (Loss), Reclassification, after Tax
Total other comprehensive earnings (losses)
Comprehensive earnings, net of tax
Comprehensive Income (Loss), Net of Tax, Including Portion Attributable to Noncontrolling Interest
Less: Comprehensive earnings (losses) attributable to noncontrolling interest
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest [Abstract]
Net earnings
Net Income (Loss) Attributable to Noncontrolling Interest
Foreign currency translation adjustments
Other Comprehensive Income (Loss), Foreign Currency Transaction and Translation Adjustment, Net of Tax, Portion Attributable to Noncontrolling Interest
Total comprehensive earnings (losses) attributable to noncontrolling interest
Comprehensive Income (Loss), Net of Tax, Attributable to Noncontrolling Interest
Comprehensive earnings attributable to W.W. Grainger, Inc.
Comprehensive Income (Loss), Net of Tax, Attributable to Parent
Schedule of Restructuring and Related Costs [Table]
Schedule of Restructuring and Related Costs [Table]
Balance Sheet Location [Axis]
Balance Sheet Location [Axis]
Balance Sheet Location [Domain]
Balance Sheet Location [Domain]
Employee Related Liabilities, Current [Member]
Employee Related Liabilities, Current [Member]
Employee Related Liabilities, Current [Member]
Income Statement Location [Axis]
Income Statement Location [Axis]
Income Statement Location [Domain]
Income Statement Location [Domain]
Selling, General and Administrative Expenses [Member]
Selling, General and Administrative Expenses [Member]
Restructuring Cost and Reserve [Line Items]
Restructuring Cost and Reserve [Line Items]
Restructuring related costs
Restructuring Costs
Restructuring reserve balance
Restructuring Reserve
Effective tax rate
Effective Income Tax Rate Reconciliation, Percent
DERIVATIVE INSTRUMENTS
Derivative Instruments and Hedging Activities Disclosure [Text Block]
Schedule of Segment Reporting Information, by Segment [Table]
Segment Reconciling Items [Member]
Segment Reconciling Items [Member]
Eliminations and Unallocated in Consolidation [Member]
Consolidation, Eliminations [Member]
Property, Plant and Equipment [Abstract]
PROPERTY, BUILDINGS AND EQUIPMENT
Property, Plant and Equipment [Table Text Block]
Disaggregation of Revenues
Disaggregation of Revenue [Table Text Block]
Schedule of Goodwill
Schedule of Goodwill [Table Text Block]
Schedule of Finite-Lived Intangible Assets By Major Class
Schedule of Finite-Lived Intangible Assets [Table Text Block]
Allowance for doubtful accounts
Accounts Receivable, Allowance for Credit Loss, Current
Cumulative preferred stock, par value (in dollars per share)
Preferred Stock, Par or Stated Value Per Share
Cumulative preferred stock, shares authorized
Preferred Stock, Shares Authorized
Cumulative preferred stock, shares issued
Preferred Stock, Shares Issued
Cumulative preferred stock, shares outstanding
Preferred Stock, Shares Outstanding
Common stock, par value (in dollars per share)
Common Stock, Par or Stated Value Per Share
Common stock, shares authorized
Common Stock, Shares Authorized
Common stock, shares issued
Common Stock, Shares, Issued
Treasury stock, shares at cost
Treasury Stock, Shares
Statistical Measurement [Axis]
Statistical Measurement [Axis]
Statistical Measurement [Domain]
Statistical Measurement [Domain]
Weighted average [Member]
Weighted Average [Member]
Intangible Assets [Axis]
Asset Class [Axis]
Intangible Assets [Domain]
Asset Class [Domain]
Customer lists and relationships [Member]
Customer-Related Intangible Assets [Member]
Trademarks, trade names and other [Member]
Trademarks and Trade Names [Member]
Non-amortized trade names and other [Member]
Indefinite-lived Intangible Assets [Member]
Capitalized software [Member]
Software and Software Development Costs [Member]
Total intangible assets, gross
Intangible Assets, Gross (Excluding Goodwill)
Total intangible assets, net
Finite-lived intangible assets, useful life
Finite-Lived Intangible Asset, Useful Life
Finite-lived intangible assets, gross
Finite-Lived Intangible Assets, Gross
Finite-lived intangible assets, accumulated amortization
Finite-Lived Intangible Assets, Accumulated Amortization
Finite-lived intangible assets, net
Finite-Lived Intangible Assets, Net
Indefinite-lived intangible assets, carrying amount
Indefinite-lived Intangible Assets (Excluding Goodwill)
Goodwill and Intangible Asset Impairment
Goodwill and Intangible Asset Impairment
Update to Significant Accounting Policies and New Accounting Standards
New Accounting Pronouncements, Policy [Policy Text Block]
Other Segments [Member]
Other Segments [Member]
Customer [Axis]
Customer [Axis]
Customer [Domain]
Customer [Domain]
Government Customer [Member]
Government Customer [Member]
Government Customer [Member]
Heavy Manufacturing [Member]
Heavy Manufacturing [Member]
Heavy Manufacturing [Member]
Light Manufacturing [Member]
Light Manufacturing [Member]
Light Manufacturing [Member]
Transportation [Member]
Transportation [Member]
Transportation [Member]
Healthcare Customer [Member]
Healthcare Customer [Member]
Healthcare Customer [Member]
Commercial [Member]
Commercial [Member]
Commercial [Member]
Retail/Wholesale [Member]
Retail/Wholesale [Member]
Retail/Wholesale [Member]
Contractors [Member]
Contractors [Member]
Contractors [Member]
Natural Resources [Member]
Natural Resources [Member]
Natural Resources [Member]
Other [Member]
Other [Member]
Other [Member]
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue
Revenue From Contract With Customer, Excluding Assessed Tax, Percentage Of Company-Wide Revenue
SHORT-TERM AND LONG-TERM DEBT
Debt Disclosure [Text Block]
Property, Plant and Equipment [Table]
Property, Plant and Equipment [Table]
Change in Accounting Estimate by Type [Axis]
Change in Accounting Estimate by Type [Axis]
Change in Accounting Estimate, Type [Domain]
Change in Accounting Estimate, Type [Domain]
Change in Accounting Method Accounted for as Change in Estimate [Member]
Change in Accounting Method Accounted for as Change in Estimate [Member]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Axis]
Property, Plant and Equipment, Type [Domain]
Property, Plant and Equipment, Type [Domain]
Land [Member]
Land [Member]
Building, Structures and Improvements [Member]
Building and Building Improvements [Member]
Furniture, Fixtures, Machinery and Equipment [Member]
Furniture, Fixtures, Machinery and Equipment [Member]
Furniture, Fixtures, Machinery and Equipment [Member]
Property, Buildings and Equipment [Member]
Property, Buildings and Equipment [Member]
Property, Buildings and Equipment [Member]
Right-Of-Use Assets [Member]
Right-Of-Use Assets [Member]
Right-Of-Use Assets [Member]
Property, Plant and Equipment [Line Items]
Property, Plant and Equipment [Line Items]
Property, buildings and equipment
Property, Plant and Equipment, Gross
Less: Accumulated depreciation and amortization and impairment
Accumulated Depreciation, Depletion and Amortization, Property, Plant, and Equipment
Estimated useful lives
Property, Plant and Equipment, Useful Life
Depreciation
Depreciation
Impairment charge
Property, Plant and Equipment, Transfers and Changes
Impairment charge
Impairment of Long-Lived Assets Held-for-use
GOODWILL AND OTHER INTANGIBLE ASSETS
Goodwill and Intangible Assets Disclosure [Text Block]
Schedule of Long-Term Debt Instruments
Schedule of Long-term Debt Instruments [Table Text Block]
Cover [Abstract]
Document Type
Document Type
Document Quarterly Report
Document Quarterly Report
Document Period End Date
Document Period End Date
Document Transition Report
Document Transition Report
Entity File Number
Entity File Number
Entity Registrant Name
Entity Registrant Name
Entity Incorporation, State or Country Code
Entity Incorporation, State or Country Code
Entity Tax Identification Number
Entity Tax Identification Number
Entity Address, Address Line One
Entity Address, Address Line One
Entity Address, City or Town
Entity Address, City or Town
Entity Address, State or Province
Entity Address, State or Province
Entity Address, Postal Zip Code
Entity Address, Postal Zip Code
City Area Code
City Area Code
Local Phone Number
Local Phone Number
Title of 12(b) Security
Title of 12(b) Security
Trading Symbol
Trading Symbol
Security Exchange Name
Security Exchange Name
Entity Current Reporting Status
Entity Current Reporting Status
Entity Interactive Data Current
Entity Interactive Data Current
Entity Filer Category
Entity Filer Category
Entity Small Business
Entity Small Business
Entity Emerging Growth Company
Entity Emerging Growth Company
Entity Shell Company
Entity Shell Company
Entity Common Stock, Shares Outstanding
Entity Common Stock, Shares Outstanding
Entity Central Index Key
Entity Central Index Key
Current Fiscal Year End Date
Current Fiscal Year End Date
Document Fiscal Year Focus
Document Fiscal Year Focus
Document Fiscal Period Focus
Document Fiscal Period Focus
Amendment Flag
Amendment Flag
SEGMENT INFORMATION
Segment Reporting Disclosure [Text Block]
Schedule of Effective Income Tax Rate Reconciliation
Schedule of Effective Income Tax Rate Reconciliation [Table Text Block]
Goodwill and Intangible Assets, Goodwill, Policy
Goodwill and Intangible Assets, Goodwill, Policy [Policy Text Block]
Statement of Cash Flows [Abstract]
CASH FLOWS FROM OPERATING ACTIVITIES:
Net Cash Provided by (Used in) Operating Activities [Abstract]
Provision for credit losses
Accounts Receivable, Credit Loss Expense (Reversal)
Deferred income taxes and tax uncertainties
Other Income Tax Expense (Benefit), Continuing Operations
Depreciation and amortization
Depreciation, Depletion and Amortization, Nonproduction
Net losses (gains) from sales of assets and business divestitures
Gain (Loss) on Disposition of Assets
Impairment of goodwill, intangibles and long-lived assets
Asset Impairment Charges
Stock-based compensation
Share-based Payment Arrangement, Noncash Expense
Subtotal
Adjustments, Noncash Items, to Reconcile Net Income (Loss) to Cash Provided by (Used in) Operating Activities
Change in operating assets and liabilities:
Increase (Decrease) in Operating Capital [Abstract]
Accounts receivable
Increase (Decrease) in Accounts Receivable
Inventories
Increase (Decrease) in Inventories
Prepaid expenses and other assets
Increase (Decrease) in Prepaid Expense and Other Assets
Trade accounts payable
Increase (Decrease) in Accounts Payable, Trade
Accrued liabilities
Increase (Decrease) in Other Accrued Liabilities
Income taxes - net
Increase (Decrease) in Income Taxes Payable
Other non-current liabilities
Other Operating Activities, Cash Flow Statement
Subtotal
Increase (Decrease) in Operating Capital
Net cash provided by operating activities
Net Cash Provided by (Used in) Operating Activities
CASH FLOWS FROM INVESTING ACTIVITIES:
Net Cash Provided by (Used in) Investing Activities [Abstract]
Additions to property, buildings, equipment and intangibles
Payments to Acquire Property, Plant, and Equipment
Proceeds from sales of assets
Proceeds from Sale of Property, Plant, and Equipment
Other
Payments for (Proceeds from) Other Investing Activities
Net cash used in investing activities
Net Cash Provided by (Used in) Investing Activities
CASH FLOWS FROM FINANCING ACTIVITIES:
Net Cash Provided by (Used in) Financing Activities [Abstract]
Payments against lines of credit
Repayments of Lines of Credit
Proceeds from Issuance of Long-term Debt
Proceeds from Issuance of Long-term Debt
Payments of long-term debt
Repayments of Long-term Debt
Proceeds from stock options exercised
Proceeds from Stock Options Exercised
Payments for employee taxes withheld from stock awards
Payment, Tax Withholding, Share-based Payment Arrangement
Purchases of treasury stock
Payments for Repurchase of Common Stock
Cash dividends paid
Payments of Ordinary Dividends, Common Stock
Other - net
Proceeds from (Payments for) Other Financing Activities
Net cash provided by (used in) financing activities
Net Cash Provided by (Used in) Financing Activities
Exchange rate effect on cash and cash equivalents
Effect of Exchange Rate on Cash and Cash Equivalents
NET CHANGE IN CASH AND CASH EQUIVALENTS
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents, Period Increase (Decrease), Including Exchange Rate Effect
Cash and cash equivalents at beginning of year
Cash, Cash Equivalents, Restricted Cash and Restricted Cash Equivalents
Cash and cash equivalents at end of period
Number of reportable segments
Number of Reportable Segments
UPDATE TO SIGNIFICANT ACCOUNTING POLICIES [Abstract]
UPDATE TO SIGNIFICANT ACCOUNTING POLICIES [Abstract]
UPDATE TO SIGNIFICANT ACCOUNTING POLICIES
Significant Accounting Policies [Text Block]
Schedule of Derivative Instruments
Schedule of Derivative Instruments [Table Text Block]
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value
Schedule of Derivative Instruments in Statement of Financial Position, Fair Value [Table Text Block]
Postretirement benefit plan reclassification, net of tax benefit
Other Comprehensive (Income) Loss, Defined Benefit Plan, Reclassification Adjustment from AOCI, Tax
Summary of Segment Results
Schedule of Segment Reporting Information, by Segment [Table Text Block]
Schedule of Reconciliation of Operating Earnings from Segment to Consolidated
Reconciliation of Operating Profit (Loss) from Segments to Consolidated [Table Text Block]
Schedule of Reconciliation of Assets from Segment to Consolidated
Reconciliation of Assets from Segment to Consolidated [Table Text Block]
Statement of Stockholders' Equity (Parentheticals) [Abstract]
Statement of Stockholders' Equity (Parentheticals) [Abstract]
Cash dividends paid per share (in dollars per share)
Common Stock, Dividends, Per Share, Cash Paid
PROPERTY, BUILDINGS AND EQUIPMENT
Property, Plant and Equipment Disclosure [Text Block]
REVENUE
Revenue from Contract with Customer [Text Block]
Assets
Income Statement [Abstract]
Net sales
Cost of goods sold
Cost of Goods and Services Sold
Gross profit
Gross Profit
Selling, general and administrative expenses
Selling, General and Administrative Expense
Operating earnings
Other (income) expense:
Nonoperating Income (Expense) [Abstract]
Interest expense, net
Other, net
Total other expense, net
Nonoperating Income (Expense)
Income tax (benefit) provision
Income Tax Expense (Benefit)
Net earnings
Less: Net earnings attributable to noncontrolling interest
Net earnings attributable to W.W. Grainger, Inc.
Net Income (Loss) Attributable to Parent
Earnings per share:
Earnings Per Share [Abstract]
Basic (in dollars per share)
Earnings Per Share, Basic
Diluted (in dollars per share)
Earnings Per Share, Diluted
Weighted average number of shares outstanding:
Weighted Average Number of Shares Outstanding, Diluted [Abstract]
Basic (in shares)
Weighted Average Number of Shares Outstanding, Basic
Diluted (in shares)
Weighted Average Number of Shares Outstanding, Diluted
Federal income tax
Effective Income Tax Rate Reconciliation at Federal Statutory Income Tax Rate, Amount
State income taxes, net of federal income tax benefit
Effective Income Tax Rate Reconciliation, State and Local Income Taxes, Amount
Foreign rate difference
Effective Income Tax Rate Reconciliation, Foreign Income Tax Rate Differential, Amount
Goodwill impairment
Effective Income Tax Rate Reconciliation, Nondeductible Expense, Impairment Losses, Amount
Tax benefit related to the Fabory business
Effective Income Tax Rate Reconciliation, Tax Benefit related to International Business, Amount
Effective Income Tax Rate Reconciliation, Tax Benefit related to International Business, Amount
Change in tax contingencies
Effective Income Tax Rate Reconciliation, Tax Contingency, Amount
Change in valuation allowance
Effective Income Tax Rate Reconciliation, Change in Deferred Tax Assets Valuation Allowance, Amount
Investment in foreign subsidiary
Effective Income Tax Rate Reconciliation, Repatriation of Foreign Earnings, Amount
Other, net
Effective Income Tax Rate Reconciliation, Other Adjustments, Amount
Income tax expense
ACCOUNTS RECEIVABLE AND ALLOWANCE FOR CREDIT LOSSES
Accounts Receivable, Allowance for Credit Loss [Table Text Block]